The invention relates to an electrode for generating plasma, a plasma chamber comprising the electrode and a method for the in situ analysis or in situ processing of a layer, or of the plasma.
The in situ characterization of an amorphous layer during plasma enhanced chemical vapor deposition (PECVD) is known from Li et al. (Li, Y. M., Ilsin A. M., Ngyuen H. V., Wronski C R., Collins R. W. (1991). Real-Time-Spectroscopic Ellipsometry Determination of the Evolution of Amorphous-Semiconductor Optical Functions, Bandgap, and Micrsotructure. Journal of Non-Crystalline Solids. Vol. 137, 787-790). The authors used a method of spectroscopic ellipsometry under irradiation with light at a 70° angle. Disadvantageously, the method and the ellipsometer used only provide a comparatively limited amount of information on the layer properties.
Wagner et al. (Wagner V., Drews, D., Esser, D. R., Zahn, T., Geurts, J., and W. Richter. Raman monitoring of semiconductor growth. J. Appl. Phys. 75, 7330) describe in situ Raman spectroscopy of a layer deposited using molecular beam epitaxy. The method and the design of the device used are disadvantageous in that usage is limited in terms of the type of deposition process.
The use of optical emission spectroscopy in situ for the plasma of a plasma chamber is known from Dingemans et al. (Dingemans, G.; van den Donker, M. N.; Hrunski, D.; Gordijn, A.; Kessels, W. M. M.; van de Sanden, M. C. M. (2007). In-situ Film Transmittance Using the Plasma as Light Source: A Case Study of Thin Silicon Film Deposition in the Microcrystalline Growth Regime. Proceedings of the 22nd EUPVSEC (European Photovoltaic Solar Energy Conference), Milan/Italy, Mar. 9, 2007-Jul. 9, 2007.-S. 1855-1858). Here, an optical feedthrough is provided at the counter-electrode of the plasma chamber, the feedthrough being used to examine the plasma directly through the substrate. This device is unsuitable for collecting advanced information, which is also a disadvantage.